Alloy for tabstock and can end

ABSTRACT

This application discloses 3XXX aluminum alloys useful in fabricating can ends and tabs used for opening cans, particularly AA3104 and AA3204 aluminum alloys. This application discloses 3XXX aluminum alloys useful in fabricating cans comprising a body, end and tab, particularly AA3104 and AA3204 aluminum alloys.

PRIOR RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/017,995, filed Jun. 27, 2014, the content ofwhich is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the fields of metallurgy, aluminumalloys, aluminum fabrication, and related fields. In particular, thepresent invention provides 3XXX alloys useful in fabricating can endsand tabs used for opening cans.

BACKGROUND

Can ends and tabs used to open cans are usually made from an AA5182aluminum alloy because it possesses good strength and formability. Therequirements for can ends and tabs are quite different than those forcan bodies. In general, greater strength is required for can ends andtabs, and that requirement has dictated that such can ends and tabs befabricated from an aluminum alloy, such as AA5182. AA5182 typicallycontains Mg in an amount of about 4.4% by weight (wt %), thus adding tothe cost of the alloy used for can ends and tabs. Thus, there is a needto replace the AA5182 with a more cost-effective alloy with requiredstrength.

In the can-making industry, it is widely considered that can ends andtabs made from an AA3104 alloy are not viable, because they havediminished strength compared to the current industry standard AA5182alloys, and thus, there is a need to increase thickness, which, in turn,increases costs.

SUMMARY

The terms “invention,” “the invention,” “this invention” and “thepresent invention” used herein are intended to refer broadly to all ofthe subject matter of this patent application and the claims below.Statements containing these terms should be understood not to limit thesubject matter described herein or to limit the meaning or scope of thepatent claims below. Covered embodiments of the invention are defined bythe claims, not this summary. This summary is a high-level overview ofvarious aspects of the invention and introduces some of the conceptsthat are further described in the Detailed Description section below.This summary is not intended to identify key or essential features ofthe claimed subject matter, nor is it intended to be used in isolationto determine the scope of the claimed subject matter. The subject mattershould be understood by reference to appropriate portions of the entirespecification, any or all drawings and each claim.

The present invention solves the problems in the prior art and providesa more cost-effective material alternative to the use of AA5182 alloyfor can ends and tabs. Cans include, but are not limited to, cans thatcontain food or beverages.

It has unexpectedly been found that a stay-on tab made from a 3XXXaluminum alloy, such as an AA3104 alloy or an AA3204 alloy, providessuitable strength and forms properly without undesirable crackingFurther, this stay-on tab allows for up to 100% recyclable content,thereby enhancing aluminum recycling.

It has unexpectedly been found that a can end made from a 3XXX aluminumalloy, such as an AA3104 alloy or an AA3204 alloy, provides suitablestrength and forms properly without undesirable cracking Further, thiscan end allows for up to 100% recyclable content, thereby enhancingaluminum recycling.

In one embodiment, the present invention provides a stay-on tab madefrom either an AA3104 alloy or an AA3204 alloy for use on “200” (2 inchdiameter) or “202” (2 inch ⅛″ diameter) can ends for beverage cans. In aspecific embodiment, the beverage can is the EVERCAN™ (Novelis, Atlanta,Ga.).

In another embodiment, the present invention provides a stay-on tab madefrom a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu,about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt% Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt% Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities,for example, 0.001-0.15 wt % impurities, with the remainder as Al, foruse as “200” or “202” can ends for beverage cans.

In another embodiment, the present invention provides a can end madefrom either an AA3104 alloy or an AA3204 alloy for use as “200” (2 inchdiameter) or “202” can ends for beverage cans. In a specific embodiment,the beverage can is the EVERCAN™ (Novelis, Atlanta, Ga.).

In another embodiment, the present invention provides a can end madefrom a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu,about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt% Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt% Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities,for example, 0.001-0.15 wt % impurities, with the remainder as Al, foruse as “200” or “202” can ends for beverage cans.

In one embodiment, the present invention provides a can comprising abody, can end, and tab made from a 3XXX alloy.

In still another embodiment, the present invention provides a cancomprising a body, can end, and tab made from an AA3104 alloy.

In yet another embodiment, the present invention provides a cancomprising a body, can end, and tab made from an AA3204 alloy.

In yet another embodiment, the present invention provides a cancomprising a body, can end, and tab made from a 3XXX series alloycomprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, forexample, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt %impurities, with the remainder as Al.

The present invention permits higher use of recycled metal. For example,the present invention permits use of at least 75%, 80%, 85%, 90%, 95%,or 100% recycled metal.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A shows several completed 100% 200 EVERCAN™ (Novelis, Atlanta,Ga.) samples with 3XXX alloys. AA3204 & AA3104 STOLLE Xl beverage tabs(Stolle Machinery Company, LLC Centennial, Colo.) were attached to 200EVERCAN™ (Novelis, Atlanta, Ga.) ends that were produced. These tabsperformed well and presented no opening issues.

FIG. 1B shows shells produced from 3xxx alloys with 3% Mg.

FIG. 2 shows an AA3204 STOLLE X1 beverage tabs, which produced noformability problems.

FIG. 3 is a schematic representation of the opening characteristics of acan end. When a can end is pulled at a certain angle, it pops. The pop(opening) is shown at around 26 degrees and 3 lbs, which is representedby the solid line. The dotted lines represent a normal specificationlimitation being used in the industry. The top dotted line representsthe maximum of the specification and the bottom dotted line representsthe minimum of the specification. The solid line at the bottomrepresents the standard deviation of the opening data. After the pop,the end continues to open until fully opened at around 63 degrees and3.5 lbs (tear).

FIG. 4 is a tabular representation of 7 groups of alloy samples. Thegrey rows represent the tabulator tab strength in pounds for the 7groups of alloy samples.

FIG. 5 is a schematic representation of average cold opening pop valuesfor the 7 groups of alloy samples in FIG. 4. The solid lines representspecification limitations used in the industry.

FIG. 6 is a schematic representation of average cold opening tear valuesfor the 7 groups of alloy samples in FIG. 4. The solid lines representspecification limitations used in the industry.

FIG. 7 is a schematic representation of a tab failure. The tab is turned90 degrees so it can't open and then pulled until it bends (fails). Asshown in the figure, with 5 lbs of pressure pulled at approximately 56degrees, failure occurs.

DETAILED DESCRIPTION

In this description, reference is made to alloys identified by AAnumbers and other related designations, such as “series.” For anunderstanding of the number designation system most commonly used innaming and identifying aluminum and its alloys, see “International AlloyDesignations and Chemical Composition Limits for Wrought Aluminum andWrought Aluminum Alloys” or “Registration Record of Aluminum AssociationAlloy Designations and Chemical Compositions Limits for Aluminum Alloysin the Form of Castings and Ingot,” both published by The AluminumAssociation.

The present invention solves the problems in the prior art and providesa cost-effective alternative to the use of AA5182 aluminum alloy for canends and tabs. Cans include, but are not limited to, cans that containfood or beverages.

It has also unexpectedly been found that a can end made from a 3XXXaluminum alloy, such as an EVERCAN™ AA3104 alloy or an EVERCAN™ AA3204alloy, provides good strength, resists deformation, such as cracking,reduces the weight of the can, and reduces the cost of producing such acan. Further, a stay-on tab produced from a 3XXX EVERCAN™ alloy allowsfor up to and including 100% recyclable content, thereby decreasing costand enhancing aluminum recycling.

In one embodiment, the present invention provides a stay-on tab madefrom either an EVERCAN™ AA3104 alloy or an AA3204 alloy for use on “200”or “202” can ends for beverage cans. In a specific embodiment thebeverage can is the EVERCAN™ (Novelis, Atlanta, Ga.).

In another embodiment, the present invention provides a stay-on tab madefrom a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu,about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt% Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt% Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities,for example, 0.001-0.15 wt % impurities, with the remainder as Al, foruse as “200” or “202” can ends for beverage cans.

In another embodiment, the present invention provides a can end madefrom either an AA3104 alloy or an AA3204 alloy for use as “200” or “202”can ends for beverage cans. In a specific embodiment the beverage can isthe EVERCAN™ (Novelis, Atlanta, Ga.).

In addition, the stay-on tab and can ends may be used on 200 or 202diameter can ends made from either an AA3104 alloy or an AA3204 alloy.This in turn, allows for lower costs and higher use of recycled metal,up to and including 100% recyclable content.

In another embodiment, the present invention provides a can end madefrom a 3XXX series alloy comprising: about 0.15-0.40 wt % Si, about0.30-0.55 wt % Fe, up to 0.10 wt % Cu, for example, 0.001-0.10 wt % Cu,about 0.70-0.90 wt % Mn, about 0.50-3.10 wt % Mg, for example, about 2wt % or about 3 wt % Mg, up to 0.05 wt % Cr, for example, 0.001-0.15 wt% Cr, up to 0.15 wt % Zn, for example, 0.001-0.15 wt % Zn, up to 0.05 wt% Ti, for example, 0.001-0.05 wt % Ti, and up to 0.15 wt % impurities,for example, 0.001-0.15 wt % impurities, with the remainder as Al, foruse as “200” or “202” can ends for beverage cans.

In one embodiment, the present invention provides a can comprising abody, can end and tab made from a 3XXX alloy.

In still another embodiment, the present invention provides a cancomprising a body, can end and tab made from an AA3104 alloy.

In yet another embodiment, the present invention provides a cancomprising a body, can end and tab made from an AA3204 alloy.

In yet another embodiment, the present invention provides a cancomprising a body, can end and tab made from a 3XXX series alloycomprising: about 0.15-0.40 wt % Si, about 0.30-0.55 wt % Fe, up to 0.10wt % Cu, for example, 0.001-0.10 wt % Cu, about 0.70-0.90 wt % Mn, about0.50-3.10 wt % Mg, for example, about 2 wt % or about 3 wt % Mg, up to0.05 wt % Cr, for example, 0.001-0.15 wt % Cr, up to 0.15 wt % Zn, forexample, 0.001-0.15 wt % Zn, up to 0.05 wt % Ti, for example, 0.001-0.05wt % Ti, and up to 0.15 wt % impurities, for example, 0.001-0.15 wt %impurities, with the remainder as Al.

The present invention permits higher use of recycled metal, furtherdecreasing costs. For example, the present invention permits use of atleast 75%, 80%, 85%, 90%, 95%, or 100% recycled metal.

Chemical compositions of AA3104 and AA3204 aluminum alloys are known toone of ordinary skill in the art and are available in the Teal sheets ofthe Aluminum Association.

In different embodiments, the stay-on tab may be coated with a BPA-Freeor BPA-NI (Bisphenol-A Free or Bisphenol-A Non-Intent) coating, alaminate, or with standard roll coatings. Further, the stay-on tab maybe of various designs and colors for marketing or promotional purposes.

In different embodiments, the can end may be coated with a BPA-Free orBPA-NI coating, laminate, or standard roll coating. Further, the can endmay be of various designs and colors.

In different embodiments, the can body may be coated with a BPA-Free orBPA-NI coating, laminate, or standard roll coating. Further, the canbody may be of various designs and colors.

This stay-on tab and can end may be used for any application thatrequires a tab to open a can, such as beverage and/or food can.

The aluminum alloy of the present invention was rolled using the singlestand cold mill route. This single stand process route also increasesthe material strength due to the nature of the heat buildup anddissipation in the coil. The material may also be produced using atandem or multi-stand cold mill practice.

The typical ultimate tensile strength range for alloys of the presentinvention in an unleveled condition is 46-51 kilopounds per square inch(ksi). The typical yield strength range for alloys of the presentinvention in an unleveled condition is 43.5-48.5 ksi, with an elongation>3.

The AA3104 and AA3204 tab samples were produced with Novelis' new stateof the art STOLLE X1/X2 beverage tab die system (die designed andproduced by STOLLE SIDNEY a division of Stolle Machinery Company, 2900Campbell Road, Sidney, Ohio 45365). The tabs were attached to a 200EVERCAN™ (Novelis, Atlanta, Ga.) can end.

The following examples will serve to further illustrate the presentinvention without, at the same time, however, constituting anylimitation thereof On the contrary, it is to be clearly understood thatresort may be had to various embodiments, modifications and equivalentsthereof which, after reading the description herein, may suggestthemselves to those skilled in the art without departing from the spiritof the invention. During the studies described in the followingexamples, conventional procedures were followed, unless otherwisestated. Some of the procedures are described below for illustrativepurposes.

Example 1

Formability performance tests were performed by producing tabs withSTOLLE commercial X1 beverage tab tooling in a Minster 100 tonconversion press utilizing CDL commercial tooling. The tabs wereinitially optically evaluated for cracking on a Zeiss AxioCam MRc5Microscope System @ 50X. The tabs were then finally evaluated andphotographed on a NIKON IMAGE ANALYSIS system using standard evaluationtechniques and procedures. Opening tests on two types of industrystandard commercial testers, an ALTEK “POP & PULL” tester and a TRAC tabtesting machine, indicates the Tab Formability to be adequate for the200 EVERCAN end design. STOLLE X1 beverage tabs produced with the AA3104or AA3204 aluminum alloys displayed no formability or cracking issues.

All patents, publications and abstracts cited above are incorporatedherein by reference in their entirety. Various embodiments of theinvention have been described in fulfillment of the various objectivesof the invention. It should be recognized that these embodiments aremerely illustrative of the principles of the present invention. Numerousmodifications and adaptations thereof will be readily apparent to thoseskilled in the art without departing from the spirit and scope of thepresent invention as defined in the following claims.

1. A can tab comprising a 3XXX aluminum alloy.
 2. The can tab of claim1, wherein the 3XXX aluminum alloy comprises about 0.15-0.40 wt % Si,about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn,about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.
 3. Thecan tab of claim 1, wherein the 3XXX aluminum alloy comprises about 2%Mg or about 3% Mg.
 4. The can tab of claim 1, wherein the 3XXX aluminumalloy is a AA3104 aluminum alloy or a AA3204 aluminum alloy.
 5. A canend comprising a 3XXX aluminum alloy.
 6. The can end of claim 5, whereinthe 3XXX aluminum alloy comprises about 0.15-0.40 wt % Si, about0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn, about0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to 0.05 wt% Ti, and up to 0.15 wt % impurities, with remainder Al.
 7. The can endof claim 5, wherein the 3XXX aluminum alloy comprises about 2% Mg orabout 3% Mg.
 8. The can end of claim 5, wherein the 3XXX aluminum alloyis a AA3104 aluminum alloy or a AA3204 aluminum alloy.
 9. The can end ofclaim 5, wherein the can end is a 2 inch diameter can end or a 2 inch ⅛″diameter can end.
 10. An aluminum can comprising a tab comprising a 3XXXaluminum alloy, an end comprising a 3XXX aluminum alloy, or both the taband the end comprise a 3XXX aluminum alloy.
 11. The aluminum can ofclaim 10, wherein the can comprises the tab comprising a 3XXX aluminumalloy and the end comprising a 3XXX aluminum alloy.
 12. The aluminum canof claim 11, wherein the can further comprises a body comprising a 3XXXaluminum alloy.
 13. The aluminum can of claim 10, wherein the tabcomprises a 3XXX aluminum alloy comprising about 0.15-0.40 wt % Si,about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn,about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.
 14. Thealuminum can of claim 10, wherein the tab comprises a 3XXX aluminumalloy comprising about 2% Mg or about 3% Mg.
 15. The aluminum can ofclaim 10, wherein the tab comprises a AA3104 aluminum alloy or a AA3204aluminum alloy.
 16. The aluminum can of claim 10, wherein the endcomprises a 3XXX aluminum alloy comprising about 0.15-0.40 wt % Si,about 0.30-0.55 wt % Fe, up to 0.10 wt % Cu, about 0.70-0.90 wt % Mn,about 0.50-3.10 wt % Mg, up to 0.05 wt % Cr, up to 0.15 wt % Zn, up to0.05 wt % Ti, and up to 0.15 wt % impurities, with remainder Al.
 17. Thealuminum can of claim 10, wherein the end comprises a 3XXX aluminumalloy comprising about 2% Mg or about 3% Mg.
 18. The aluminum can ofclaim 10, wherein the end comprises a AA3104 aluminum alloy or a AA3204aluminum alloy.
 19. The aluminum can of claim 10, wherein the end is a 2inch diameter end or a 2 inch ⅛″ diameter end.
 20. The aluminum can ofclaim 10, wherein the can is a beverage can or a food can.